As indicated in appended drawing FIGS. 1 and 2, upholstered seating furniture (e.g. A) of the prior art generally comprises: a rearwardly positioned upright backrest (B); a forwardly positioned horizontal seat (C) (the backrest and seat portions being centrally intersected by a vertical central-plane (10C)); and substrate-abuttable legs (D) depending from the horizontal seat portion (C). Upright backrests typically and internally skeletally comprise a pair of vertical side members (12A, 12B) that flank said central-plane (10C) and each being positioned along a vertical rearward-plane (10R) and a vertical forward-plane (10F), each of said planes 10R and 10F perpendicularly intersecting central-plane 10C. Typically employed for completing the internal structural skeleton for a seating backrest (B) are horizontal members 11A and 11B, each of which is attached to sidemembers 12A and 12B. Customarily attached to the backrest internal skeletal members (12A. 12B) is a vertically-extending primary-array of horizontal and vertically-undulate metallic primary-springs (15A-15F), each of said primary-springs being attached to both sidemembers (12A, 12B) and extending concavely forwardly beyond said forward-plane 10F (and too horizontally across said central-plane 10C). The several primary-springs are tied-together at upright primary-bars 14 (that flank central-plane 10C) with clips 13 or weldings 13. Foam, or other resiliently-compressive padding (16) extends uprightly along the forward side of said primary-array (15A-15F). As best indicated by drawing FIG. 2, uprightly extending, flexible fabric upholstery material (17) surrounds the backrest sidemembers (12A, 12B) and too the reslliently-compressive frontal padding (16) for primary-springs (15A-15F). Thus, whenever a furniture occupant (seated upon the horizontal seat portion (C)) recumbantly leans his/her upper-body rearwardly, the several primary-springs (15A-15F) and the frontal padding (16) will concommittantly rearwardly flex, to thusly provide a modicum of upperbody comfort to the seated occupant. However, with the conventional prior art structure described hereabove, a seated occupant, rearwardly recumbently leaning along vertical-plane 10C, will sense the insecurity of being unrestrained in the horizontal directions from vertical central-plane 10C.